The ever-increasing demand for smaller sized mobile devices, such as cell phones, digital cameras, etc. has correspondingly triggered a growing need for smaller sized photography modules contained therein. Size reductions may be contributed from various aspects of the mobile devices, which includes not only the charge-coupled device (CCD) and the complementary metal-oxide semiconductor (CMOS), but also the optical imaging lens mounted therein. When reducing the size of the optical imaging lens; however, achieving good optical characteristics becomes a challenging problem.
U.S. Pat. Nos. 7,715,119, 7,848,032, 8,089,704, 7,920,340, US Patent Publication No. 2011009572, U.S. Pat. Nos. 7,777,972, 7,969,664 and 7,274,518 all disclosed an optical imaging lens constructed with an optical imaging lens having four lens elements. In the first embodiment of U.S. Pat. No. 7,920,340, the length of the optical imaging lens is over 7 mm, which is not beneficial for the smaller design of mobile devices.
How to effectively shorten the length of the optical imaging lens is one of the most important topics in the industry to pursue the trend of smaller and smaller mobile devices.
Therefore, there is needed to develop optical imaging lens with a shorter length, while also having good optical characteristics.